The present invention pertains to a fastener system, and more particularly a fastener system for use in joining a composite panel or the like to a section of metal framing, as is used in the construction of large shipping containers, truck trailers or truck bodies.
In the last several years, the transportation industry has moved rapidly toward usage of shipping containers. These units constitute a valuable and necessary labor saving device, in that once loaded they can be transported by rail, truck or ship without the necessity of unloading and reloading the contents. While these containers may be of varied construction, they mainly are fabricated from fiberglass, reinforced polyester plywood panels which are fastened to a metal framework. Metal panels are used in some constructions, especially where an insulated container is desired. In addition to shipping containers, trailer truck bodies are also now being constructed in a similar manner.
It should be noted, that a great number of joints are required in the assembly of each container or trailer body; for example, a normal 40-foot trailer will require between 500 and 600 separate fastener assemblies or joints. Accordingly, the time and/or labor required in the seating of the fastener assembly for each joint is a significant factor in the overall production costs. In addition to being easily and economically installed, each fastener assembly must also be vibration-proof; tamper-proof to prevent thefts in transit; and water-tight so that moisture cannot enter and weaken the plywood laminate. The fastener assembly of the present invention provides the abovementioned features, and additional advantages that are not obtained with the prior art assemblies presently being used in container constructions, as will be explained in some detail hereinafter.
Consideration is now directed briefly to the prior art type of fastener systems used in container constructions. In this regard, these systems normally employ a deformable sleeve member and an elongate bolt member which is provided with a frangible section at some intermediate point along the length thereof. A special tool is used which is engaged with the end portion of the bolt member on the side of the frangible section opposite the bolt head, which tool effects deformation of the sleeve into gripping engagement with a portion of the bolt on the opposite side of the frangible section, to achieve the fastener joint. During the deformation of the sleeve, the tool imparts a tensile stress or loading to the bolt which eventually fractures the frangible section, breaking off the distal end engaged by the tool, which end is then discarded.
While the prior art types of fastener systems have been used extensively, they are possessed of a number of inherent disadvantages that are overcome by the present invention. For example, once installed, these prior art systems cannot be adjusted, if preloading is lost due to expansion or contraction of the panel, or the bolt member itself. In addition, these fasteners, once assembled cannot be easily replaced for maintenance purposes, such as to repair damage to the container. These prior art assemblies not only require special tooling, but the assembly thereof required a two-man operation, in most applications. An individual must be stationed on each side of the panel, the first to position the bolt in a preformed aperture in the framing and the panel sections, and the other to operate the special deforming tool. Also, the fractured portion of the bolt, which is discarded, constitutes waste that bears on the initial cost of the fastener, which of course must be borne by the manufacturer.
The present invention not only provides a vibration-proof, tamper proof and moisture-proof joint, but does so in a manner which overcomes the above-discussed disadvantages of the prior art assemblies. That is to say, the present invention may be easily installed by one individual, it can be reseated or tightened should preloading become lost; it can be easily replaced; and since it utilizes no special tooling or waste material, the overall cost of the fastener system is reduced.
Briefly, the fastener system of the present invention achieves the above-discussed advantages due to its unique constructions. In this regard, it should be noted that there is provided a novel bolt member that is adapted for mating engagement with a specially constructed nut member to achieve the desired clamping action between the frame and the panel sections. The bolt member includes means which enable it to be set initially in the frame aperture in a manner which precludes rotation thereof and achieves centering of the threaded end portion thereof relative to the panel aperture. Accordingly, a single worker can set a number of these bolt members, and then subsequently engage the nut members therewith to complete the joint. It should be noted that the member of the system which is engaged with the metal frame, i.e., the exterior of the container, is provided with a tamper-proof head, and means to seal against the entry of moisture. The member of the fastener assembly disposed internally of the container includes a drive recess for engagement by a standard power-driven wrench or the like.
Numerous other advantages of the present invention will become more apparent from the detailed description of the drawings and the illustrated embodiments, which follows hereinafter.